House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell, R-Ky., both sharply denounced Trump's comments in statements. Ryan also asked Trump not to appear at a scheduled campaign stop in his home state of Wisconsin on Saturday.
Republican strategists warned that the new revelations would be likely to hurt Trump, especially with women voters. Meanwhile, vulnerable GOP down-ballot candidates and sitting lawmakers either sought to distance themselves quickly or remained eerily silent.
“His comments are totally inappropriate and offensive,” said Republican Sen. Kelly Ayotte (N.H.), who is locked in one of the most competitive Senate races in the country.
The graphic comments, which Trump made in 2005 on a bus and on the set of a soap opera, feature him bragging about his sexual pursuit of a married woman.
“And when you’re a star they let you do it,” Trump says. “Grab them by the p---y. You can do anything.”
One by one, Democratic challengers moved quickly to tie their Republican opponents to Trump's newest statements.
By the time Ayotte released the curt one-sentence comment, her Democratic opponent, New Hampshire Gov. Maggie Hassan, had already sought to tie her to Trump, reminding voters that at a debate earlier in the week, she called Trump a role model.
“These vile comments from Donald Trump cannot be excused,” Hassan said in a statement. "It is beyond comprehension how Sen. Ayotte could continue to support this man for the highest office in the land, let alone call him a role model.”
One by one, Democratic Senate candidates in key races, including Arizona and Ohio, joined in.
"Everyone in America is disgusted and fed up with Donald Trump — except Senator Portman,” said a spokesman for Ohio Democrat Ted Strickland's senate campaign, David Bergstein. "Senator Portman's continued support for Trump is equal parts pathetic and offensive, but that's what Ohioans have come to expect from a lapdog like Portman.
"If Portman won't stand up to Trump, there's no way Ohioans can trust him to stand up for us in the Senate,” he added.
Other Republicans warned that the comments combined with the timing — just days before the second presidential debate in St. Louis — could leave a mark.
"This one will cause real damage,” Republican pollster Frank Luntz said.
Women are already a challenging demographic for Trump in many battleground states, and Republicans' swift reaction to these latest revelations signal how damaging they think it could be for the party and the Republican nominee.
Longtime Trump foe Jeb Bush signaled that Trump's couched apology was insufficient.
"As the grandfather of two precious girls, I find that no apology can excuse away Donald Trump's reprehensible comments degrading women,” Bush tweeted.
Sen. Mark Kirk (R-Ill.) who has long been a vocal critic of Trump, exploded on Twitter.
"DJT is a malignant clown — unprepared and unfit to be president of the United States,” Kirk said.
And former Utah Gov. Jon Huntsman, a Republican who recently said he would vote for Trump, called for Trump to resign.
"In a campaign cycle that has been nothing but a race to the bottom — at such a critical moment for our nation — and with so many who have tried to be respectful of a record primary vote, the time has come for Governor Pence to lead the ticket," Huntsman told The Salt Lake Tribune.
Mitt Romney, the 2012 Republican nominee who has vocally criticized Trump said that Trump's comments "corrupt America's" image to the world.
Hitting on married women? Condoning assault? Such vile degradations demean our wives and daughters and corrupt America's face to the world.— Mitt Romney (@MittRomney) October 8, 2016
But Trump's Virginia campaign chairman Corey A. Stewart insisted that women voters wouldn't be moved by Trump's comments.
“When people voted for Donald Trump, they knew he wasn’t an angel,” said Stewart, a 2017 contender for Virginia governor and chairman of the Prince William Board of County Supervisors. “They are not concerned that, at times, Donald Trump acts like a frat boy. Sometimes he does, but that’s okay.”
"They know he’s not an angel. They know that he can save the country, though,” he added.
Florida-based Republican strategist Al Cardenas questioned whether these remarks might become yet another controversial remark from Trump that failed to move the needle in this election.
"The query is whether after 50-plus outlandish, offensive comments towards women and minorities by Mr. Trump, is this one so over the top over the others that it will finally make a difference with voters where others have not?” Cardenas mused. "It does seem to reach new lows.”
Trump was expected to appear for the first time on the campaign trail with House Speaker Paul D. Ryan in Wisconsin on Saturday. But Friday night, Ryan, in condemning Trump's comments, said that Trump would no longer appear at the event.
“I am sickened by what I heard today,” Ryan said in a statement. “Women are to be championed and revered, not objectified. I hope Mr. Trump treats this situation with the seriousness it deserves and works to demonstrate to the country that he has greater respect for women than this clip suggests.”
Meanwhile, Trump's running mate, Mike Pence, campaigned in Ohio and reporters noted that a small group of journalists who usually travel with the Indiana governor were abruptly ushered out of a restaurant where he was eating and campaigning. He did not respond to questions shouted by reporters.
Hillary Clinton's aides expect the issue to be a major one in Sunday night's debate at Washington University.
Before then, however, the campaign has been galvanizing supporters with the new revelations, encouraging them to register to vote and to donate to the campaign.
Top Clinton aides and Congressional Democrats also indicated that they would seek to hold Republicans accountable for failing to rescind their support for Trump.
"This is a moment of truth for Republicans," said Senate Minority Leader Harry Reid, D-NV. "It is time for every Republican elected official in this county to revoke their endorsements of Donald Trump and state that they will not vote for their party's nominee, who has been caught on tape bragging about routinely sexually assaulting women.
"There is no way to defend the indefensible. In the name of decency, Republicans should admit that this deviant - this sociopath - cannot be president," he added.
And how Trump handles the questioning at the debate on Sunday could help determine how much of an impact it has on voters, said Sarah Isgur Flores, a Republican strategist and former deputy campaign manager to presidential hopeful Carly Fiorina.
"It's an understatement to say this now means Trump heads into Sunday's debate on defense, which hasn't worked out well for a candidate that has trouble staying on message even under normal circumstances,” Flores said. "That being said, there's a huge overlap between Trump voters and voters who already think Trump is a risky bet.
"So unclear whether this alone will move numbers, but it does make his ability to handle it at the debate in 48 hours wildly more important,” she added.
In a statement, Trump described the recording as "locker room banter” and apologized "if anyone was offended.”
But allies of Hillary Clinton called it something else: sexual assault.
"Donald Trump apparently thinks he has the right to sexually assault women because he's famous,” said NARAL Pro-Choice America National Communications Director Kaylie Hanson Long. "Never mind consent, he doesn't think he needs it.
"He's not a role model, he's vulgar and dangerous, and his disregard for women has never been more clear,” she added.
Dawn Laguens, executive vice president of Planned Parenthood Action Fund, predicted in an interview that it would sink his candidacy.
"If someone, quote, grabbed someone by the p---y, to quote Donald Trump, on a subway or on a bus or at a school, they would be in jail. They would be arrested and prosecuted, and they would go to jail,” Laguens said. "I think we are now moving to the end of the end of Donald Trump.”
The Clinton campaign's deputy communications director Christina Reynolds added: "This is horrific. We cannot allow this man to become president.”
Sean Sullivan and Laura Vozzella contributed to this report from Washington.